Chapter 37: Electromagnetic Induction 37.1 ·The making of voltage is based on the relative motion between the conductor and the magnetic field. ·Electromagnetic Induction:inducing voltage by changing the magnetic field around a conductor ·The larger the number of loops of wire that go in a magnetic field, the bigger the induced voltage and current will be in the wire ·Fast motion makes a greater voltage.
37.2 ·Faraday's Law "The induced voltage in a coil is proportional to the product of the number of loops and the rate at which the magnetic field changes within these loops.” ·The total current made by electromagnetic induction also depends on the resistance of the coil and the circuit its connected to ·Example: you can throw a magnet in and out of a blocked rubber loop and in and out of a closed loop of copper. The voltage will be the same for both ·The bonding for the copper and rubber to the permanent atoms stops movement of charge that happens so open in the copper one 37.3 ·If one part of a magnet is blocked in and out of a wire coil then the induced voltage changes direction ·When the magnetic field force weakens then the voltage is induced in the opposite direction ·Generator: Rotating the coil in a stationary magnetic field
·A generator is the opposite of a motor ·A motor switches electrical energy into mechanical energy ·A generator switches mechanical energy into electrical energy ·The voltage made by the generator changes and the current formed is changing alternating current (ac) ·The current sometimes changes magnitude and direction ·The average alternating current in the United States changes its magnitude and direction during 60 series per second which is 60 hertz ·Big coils make many loops of wire wrap on an iron core, which makes a frame a lot like the frame of a motor ·The frame is linked on the outside to a turbine ·Energy from wind or falling water can be used to make the turbine work while most generators get power by moving steam 37.4 ·“Moving charges experience a force that is perpendicular to both the ir motion and the magnetic field they traverse” ·The redirected wire is the motor result and the law of induction is the generator result 37.5 ·The coil linked to the power source is the primary which isinput and the other coil is the secondary which is output ·When the switch is stopped in the primary and current go’s through its coil a current also go’s in the secondary. ·When the primary is opened a flow of current registers in the secondary but go’s in the opposite direction ·The magnetic field is focused in the middle which go’s into the secondary ·The secondary catches more of the field change ·Transformer: is a device for increasing or decreasing voltage through electromagnetic induction
·The relation that voltage will change is equal to the ratio of the amount of turns on the output coil to the number of turns on the input coil ·The full power controlled by the transformer is the same in both coils 37.6 ·Electric utilities provide power in the form of changing current ·Power can be carried from power plants to cities at 120000 volts or more ·Power is sends big distances at high voltages and also low currents 37.7 ·The new version of Faraday’s Law: “An electric field is created in any region of space in which a magnetic field is changing with time. The magnitude of the created electric field is proportional to the rate at which the magnetic field changes. The direction of the created electric field is at right angles to the changing magnetic field.” ·If a charge is in a changing magnetic field then it will occur with a force from the electric field ·James Clark Maxwell made a complement to Faraday’s Law to guess the effect of change in an electric field ·“A magnetic field is created in any region of space in which an electric field is changing with time. The magnitude of the created magnetic field is proportional to the rate at which the electric field changes. The direction of the created magnetic field is at right angles to the changing electric field.” 37.8 ·When an electric current is present it will generate a magnetic field but the changing magnetic field around a changing current will generate an electric field ·Electromagnetic Wave: a wave that is partly electric and partly magnetic and carries energy. Emitted by vibrating electric charges. ·Electromagnetic waves are changing electric and magnetic fields that go at the same rate and support each other ·The only pace waves can move is the speed of light
Chapter 37: Electromagnetic Induction
37.1
· The making of voltage is based on the relative motion between the conductor and the magnetic field.
· Electromagnetic Induction: inducing voltage by changing the magnetic field around a conductor
· The larger the number of loops of wire that go in a magnetic field, the bigger the induced voltage and current will be in the wire
· Fast motion makes a greater voltage.
37.2
· Faraday's Law "The induced voltage in a coil is proportional to the product of the number of loops and the rate at which the magnetic field changes within these loops.”
· The total current made by electromagnetic induction also depends on the resistance of the coil and the circuit its connected to
· Example: you can throw a magnet in and out of a blocked rubber loop and in and out of a closed loop of copper. The voltage will be the same for both
· The bonding for the copper and rubber to the permanent atoms stops movement of charge that happens so open in the copper one
37.3
· If one part of a magnet is blocked in and out of a wire coil then the induced voltage changes direction
· When the magnetic field force weakens then the voltage is induced in the opposite direction
· Generator: Rotating the coil in a stationary magnetic field
· A generator is the opposite of a motor
· A motor switches electrical energy into mechanical energy
· A generator switches mechanical energy into electrical energy
· The voltage made by the generator changes and the current formed is changing alternating current (ac)
· The current sometimes changes magnitude and direction
· The average alternating current in the United States changes its magnitude and direction during 60 series per second which is 60 hertz
· Big coils make many loops of wire wrap on an iron core, which makes a frame a lot like the frame of a motor
· The frame is linked on the outside to a turbine
· Energy from wind or falling water can be used to make the turbine work while most generators get power by moving steam
37.4
· “Moving charges experience a force that is perpendicular to both the ir motion and the magnetic field they traverse”
· The redirected wire is the motor result and the law of induction is the generator result
37.5
· The coil linked to the power source is the primary which is input and the other coil is the secondary which is output
· When the switch is stopped in the primary and current go’s through its coil a current also go’s in the secondary.
· When the primary is opened a flow of current registers in the secondary but go’s in the opposite direction
· The magnetic field is focused in the middle which go’s into the secondary
· The secondary catches more of the field change
· Transformer: is a device for increasing or decreasing voltage through electromagnetic induction
· The relation that voltage will change is equal to the ratio of the amount of turns on the output coil to the number of turns on the input coil
· The full power controlled by the transformer is the same in both coils
37.6
· Electric utilities provide power in the form of changing current
· Power can be carried from power plants to cities at 120000 volts or more
· Power is sends big distances at high voltages and also low currents
37.7
· The new version of Faraday’s Law: “An electric field is created in any region of space in which a magnetic field is changing with time. The magnitude of the created electric field is proportional to the rate at which the magnetic field changes. The direction of the created electric field is at right angles to the changing magnetic field.”
· If a charge is in a changing magnetic field then it will occur with a force from the electric field
· James Clark Maxwell made a complement to Faraday’s Law to guess the effect of change in an electric field
· “A magnetic field is created in any region of space in which an electric field is changing with time. The magnitude of the created magnetic field is proportional to the rate at which the electric field changes. The direction of the created magnetic field is at right angles to the changing electric field.”
37.8
· When an electric current is present it will generate a magnetic field but the changing magnetic field around a changing current will generate an electric field
· Electromagnetic Wave: a wave that is partly electric and partly magnetic and carries energy. Emitted by vibrating electric charges.
· Electromagnetic waves are changing electric and magnetic fields that go at the same rate and support each other
· The only pace waves can move is the speed of light